Electric fuse



13, 1929. J. H. HICKEY 1,724,022

ELECTRIC FUSE Filed March 28, 1,927

'INVENTOR JOHN H. HICKEY ATTY Patented Aug. 13, 1929.

UNITED STATES JOHN H. HICKEY, OF SAN FRANCISCO, CALIFORNIA.

ELECTRIC FUSE.

Application filed March 28, 1927.

My invent-ion relates to improvements in electric fuses wherein the fusible element is normally fully enclosed and is rendered conveniently observable for purposes of mspec tion when desired, and is an improvementupon the device shown in my copending application, Serial No. 144,008, filed Oct. 20, 1926.

The primary object of the present invention is to provide an improved fuse adapted to render the fusible element observable to facilitate inspection.

Another object is to provide an improved construction wherein the fusible element is normally fully encasechbut will permit the fuse to be easily opened for inspection.

A further object is to provide an improved fuse casing provided with a movable shutter adapted to render the fuse observable and arranged to normally close the casing and to reinforce and strengthen the same.

Another object is to provide an improved device of the character described wherein a Shutter is normally maintained in closed position and arranged to be automatically returned to said closed position after said shutter has been moved to render the fusible element observable.

A further object is to provide an improved construction which is extremely strong and durable'and adapted for service in high tension circuits.

I accomplish these and other objects by means of the improved device disclosed in the drawings forming a part of the present application wherein like characters of reference are used to designate similar parts throughout the specification and drawings, and in which,

Fig. 1 is a broken side elevation, partly in longitudinal section ,of my improved electric fuse.

Fig. 2 is a similar view with the fuse turned through ninety degrees from the position shown in Fig. 1.

Fig. 3 is a transverse section taken upon the line 33 of Fig. 2 in the direction indicated.

Fig. 4 is a transverse section taken upon the line H of Fig. 2 in the direction indicated.

Fig. 5 is an end elevation of my improved fuse, portions being broken away.

Referring to. the drawings, the numeral Serial No. 179,008.

1 is used to designate in general a casing member upon the ends of which are detachably mounted a pair of contact members 2, secured upon the casing by. means of collars 3 threaded onto the, ends of the casing 1. One or more fusible elements l, of calculated current carrying capacity, are detachably secured between connecting members 6 which, in turn, are preferably detachably connected to the cont-act members 2.

The casing member 1 has a pair of openings 7 formed in opposite sides thereof whereby the fusible element 4L may be observed. A shutter casing 8 is mounted upon the casing member 1 to normally close the openings 7, said shutter preferably consisting of a cylindrical member rotatably mounted upon the member 1 and having a pair of openings 9 arranged to be moved into registering relation with the openings 7 in the casing member 1. The shutter member forms a close sliding fit around the casing 1 and extends substantially the full length of the casing 1 between the collars The shutter casing S is normally held in close position by means of a suitable spring 11 having one end connected to a post 12 secured upon the shutter, and the other end connected upon a post 14: secured upon the casing 1 and extending outwardly through a slot 16 formed in the shutter 8. The slot 16 is made of a length to limit the rotative movement of the shutter 8 upon the casing 1. The slot 16 also holds the shutter 8 against longitudinal movement by virtue of its engagement with the post 14. The slot 16 is also positioned so that when the shutter 8 is moved to one extreme position the openings 9 will be moved into spaced relation to the openings 7 and a solid portion of the shutter will extend across and close said openings 7. \Vhen the casing is moved to the opposite extreme position against the tension of the spring 11, the openings 9 are caused to register with the openings 7 and the fusible element 4 is thereby rendered clearly visible through the opposite registering openings.

In operation, the fusible element 4 is assembled into the fuse by bolting or otherwise securing said elemcnts -it upon the connecting member 6. One of said members is then bolted or clamped into engagement with acontact member 2, preferably by means of a clamping block 17 engaging a lug 18 forming part of the connecting memher 6. The contact member is then secured upon one end of the casing 1 upon which. the shutter 8 is mounted by a collar 3. The connecting member 6 upon the opposite end then has the other contact member 2 clamped thereto, and the opposite collar 3 applied to firmly bind the fuse into assembled relation.

The fuse is now applied in a fuse block and operates in the ordinary manner. When it desired to inspect the fuse for any reason, as when it becomes necessary to locate a blown fuse or the like, the shutter 8 is rotated against the tension of the spring 11 from the normal position shown in full lines to the open position indicated in dotted lines in A igs. 8 and A of the drawings. The operator may now look hrough the registcring openings 7 and 9 and observe the condition of the fusible element within the casing 1 without removing the fuse from its block. lVhen the shutter 8 is released, the spring 11 operates to automatically return the shutter to closed position.

The casing 1 and shutter 8 are made of tubular insulating material of any suitable character adapted to withstand the blowing of a high tension fuse. In ordinary ser' ice, the shutter S reinforces the casing 1 over substantially the entire area thereof, thus materially increasing the strength of the casing. The openings 7 and 9 are made relatively small so that the area of casing which is not reinforced is small and the possibility of the casing bursting is reduced to a minimum.

In order to further guard against bursting of the casing, a vent plate 19 is secured upon the inner end of each contact member 2. Notches 21 are formed around the edges of the plates 19. The plates 19 are held against the ends of the casing 1 when the fuse is assembled and the notches 21 form passages between the interior of the casing and the threads engaged by the collars 3, whereby air may expand outwardly and escape past said threads when the fuse is blown, thus forming a vent at a point rela tively remote from the openings 7 and 9.

l Vhilel have illustrated and described what I regard as the preferred construction ofmy improved electric fuse, the details of construction may, of course, be modified in numerous ways without departing from the spirit of my invention. 1, therefore, do not wish to restrict myself to the specific construction illustrated and described, but desire to avail myself of all modifications which may fall within the scope of the appended claims.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is,

1. A fuse comprising a casing provided with contacts mounted upon the ends thereof and a fusible conductor connected between said contacts within the casing, said casing having openings arranged to permit the fusible conductor to be observed; a shutter mounted upon the casing adjacent the openings and arranged to be moved to uncover said openings; and means arranged to normally move and hold the cover in a closed position.

2. A fuse comprising a casing provided with contacts mounted upon the ends thereof and a fusible conductor connected between said contacts within'the casing, said casing having openings arranged to permit the fusible conductor to be observed; a shutter rotatably mounted upon the casing adjacent the openings and arranged to be moved to uncover said openings; and resilient means arranged to normally move and hold the coverin closed position.

3. A fuse comprising a casing provided with contacts mounted upon the ends thereof and a fusible conductor connected between said contacts within the casing, said casing having openings arranged to permit the fusible conductor to be observed; a shutter mounted upon the casing adjacent the openings and arranged to be moved to uncover said openings; and a spring connected .between the shutter and the casing for normally holding the shutter in closed position.

4:. A fuse comprising a casing provided mally moving and holding the shutter in closed position with its openings out of registering relation with the openings in the casing.

5. A fuse comprising a casing provided with contacts mounted upon the ends thereof and a fusible conductor connected between said contacts within the casing, said casing having openings arranged to permit the fusible conductor to be observed; a shutter rotatably mounted upon the casing, said shutter having openings arranged to be moved to register with the openings in the casing; and a spring having one end connected upon the casing and the other end connected to the shutter for normally holding the shutter in closed position with its openings out of registering relation with the openings in the casing.

6. A fuse comprising a casing provided with contacts mounted upon the ends thereof Cir and a fusible conductor connected between said contacts within the casing, said casing having openings arranged to permit the fusible element to be observed; a shutter mounted upon the casing to normally close said openings and arranged to be moved to uncover said openings; caps threaded onto the ends of the casing to retain the contacts; and plates mounted between the ends of the casing and the contacts and having notches arranged to form a vent past the contacts to the cap retaining threads at points remote from the openings.

7. In an electric fuse, the combination with a fuse casing having openings formed in the sides thereof, of a shutter rotatably mounted upon the casing and having openings arranged to be moved into registering relation with the openings in the casing; a post mounted upon the casing and extending outwardly through a. slot formed in the shutter; a post secured upon the shutter; and a spring connected between the posts to normally hold the shutter in closed position.

8. In an electric fuse, the combination with a fuse casing having openings formed in the sides thereof, of a shutter rotatably mounted upon the casing and having openings arranged to be moved into registering relation with the openings in the casing; spring means arranged to normally move and hold the shutter in closed position with its openings out of registering relation with the openings in the casing; and means mounted adjacent the ends of the casing for forming vents therefrom at points remote from the shutter openings.

In witness whereof I hereunto set my signature.

JOHN H. HICKEY. 

